Year 11 2014 Chat :) (1 Viewer)

[Carrotsticks]

guys, how do u solve this inequality:

x^2 + 2x + 3 > 0

that is it. but i dont understand why the answer is true for all x.

Because when you complete the square, you get

But notice, that's always positive isn't it??? Go ahead, try it. Try substituting a number that DOESN'T make it > 0.

There exists no such number, so that's why it's > 0 for all real x.

 

[turnerloos]

Because when you complete the square, you get

But notice, that's always positive isn't it??? Go ahead, try it. Try substituting a number that DOESN'T make it > 0.

There exists no such number, so that's why it's > 0 for all real x.

how did i not see that... tyvm everyone for helping even though its almost 2 lol

 

[hawkrider]

Fuarr, this bio homework is harder than I expected.

 

[justem]

Fuarr, this bio homework is harder than I expected.

Do not give up, persevere

 

[justem]

My bio homework was to write up a report, pretty simple

 

[hawkrider]

My bio homework was to write up a report, pretty simple

Mine was 6 pages of the dot point book.

 

[turnerloos]

yo guys, i've got this other question which i couldnt solve.

Find the range of values of "p" for which the expression:
px^2 + (3+p)x + (3+p) is a positive definite.

 

[Soulful]

yo guys, i've got this other question which i couldnt solve.

Find the range of values of "p" for which the expression:
px^2 + (3+p)x + (3+p) is a positive definite.

Consider the definition of "positive definite" in regard to the leading coefficient and the discriminant and then try to solve it from there

 

[turnerloos]

Consider the definition of "positive definite" in regard to the leading coefficient and the discriminant and then try to solve it from there

i tried solving it:
positive definite discriminant <0 and a>0
therefore p>0

find discriminant:
i got => -3p^2 -6p +9 <0
factorised to find p, i got => (p+3)(p-2)<0
my final answer was 0<p<2 but thats apparently wrong...
what did i do wrong?

 

[Ununoctium]

G'day everyone! Nice to see some other keen 2015'ers . How are all your subjects after the first week? I had to transfer from Bio to Modern because the teacher was just terrible :'(.

 

[turnerloos]

G'day everyone! Nice to see some other keen 2015'ers . How are all your subjects after the first week? I had to transfer from Bio to Modern because the teacher was just terrible :'(.

there were mostly introductions in the first week. didnt really learn much

 

[Ununoctium]

there were mostly introductions in the first week. didnt really learn much

In Economics, we are straight into it. We're already onto production possibility curves (if you call that being far ahead). Also, Italian by distance had a bit of admin and sorting to do - it is going to be fun !

 

[Fawun]

Basically throughout the whole HSC I really disliked Legal Studies (despite doing decently in internal assessments). It was only after trials that I started appreciating the subject (read other people's essays and decided to pick up my game).

As for favourite it would definitely be Business. I wouldn't say that I truly disliked any of my subs once I finished the HSC tbh.

This

Legal studies is the worst subject hahahah

 

[Fawun]

In Economics, we are straight into it. We're already onto production possibility curves (if you call that being far ahead). Also, Italian by distance had a bit of admin and sorting to do - it is going to be fun !

Holy shit i remember learning produxtion possibility curves as if it was yesterday

Fk

 

[turnerloos]

In Economics, we are straight into it. We're already onto production possibility curves (if you call that being far ahead). Also, Italian by distance had a bit of admin and sorting to do - it is going to be fun !

class is still on economic problem... but i've done ppc/ppf - allocative efficiently. reading ahead of the class (Y)

 

[Soulful]

i tried solving it:
positive definite discriminant <0 and a>0
therefore p>0

find discriminant:
i got => -3p^2 -6p +9 <0
factorised to find p, i got => (p+3)(p-2)<0
my final answer was 0<p<2 but thats apparently wrong...
what did i do wrong?

Hmm, I think you might have made a mistake factorising
Remember, -3p^2-6p+9<0 can be simplified into a much more workable inequality

 

[turnerloos]

Hmm, I think you might have made a mistake factorising
Remember, -3p^2-6p+9<0 can be simplified into a much more workable inequality

i guess you could do this => -3(p^2-2p-3)<0 = -3[(p-1)^2 -4]<0
but how i would go from there?

 

[Soulful]

i guess you could do this => -3(p^2-2p-3)<0 = -3[(p-1)^2 -4]<0
but how i would go from there?

I think you made a mistake taking the -3 out (look at the + and - signs), but you're on the right track!

You can divide the 3 out (divide 3 from both sides, and 0/3 = 0 so the RHS doesn't change) and then you get a simple quadratic inequality (not sure what it's called)

(remember, since you are diving by a negative number, you reverse the inequality sign)

Try drawing this graph, it might help you work out what parts are above zero.

Hope this helps

 

[J280]

Aim for a band 6 in all of your subjects-you have two years to achieve your goal, say even if you are a band 4 student, in one year, you can get to a band 5, and in another year, you can get to band 6, I am sure you are much better in English-but I am just saying you've got to aim high, work hard and believe that you can achieve your dreams

Haha sorry I worded that poorly, I meant I was aiming for all band 6s but would be happy if I got those results even

 

[J280]

G'day everyone! Nice to see some other keen 2015'ers . How are all your subjects after the first week? I had to transfer from Bio to Modern because the teacher was just terrible :'(.

How are you finding your other subjects?
My week was awesome